/*
 * Copyright 2014 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.handler.codec.compression;

/**
 * Random numbers for decompress Bzip2 blocks.
 */
final class Bzip2Rand
{
    /**
     * The Bzip2 specification originally included the optional addition of a
     * slight pseudo-random perturbation to the input data, in order to work
     * around the block sorting algorithm's non- optimal performance on some
     * types of input. The current mainline bzip2 does not require this and will
     * not create randomised blocks, but compatibility is still required for old
     * data (and third party compressors that haven't caught up). When
     * decompressing a randomised block, for each value N in this array, a 1
     * will be XOR'd onto the output of the Burrows-Wheeler transform stage
     * after N bytes, then the next N taken from the following entry.
     */
    private static final int[] RNUMS =
    { 619, 720, 127, 481, 931, 816, 813, 233, 566, 247, 985, 724, 205, 454, 863,
            491, 741, 242, 949, 214, 733, 859, 335, 708, 621, 574, 73, 654, 730,
            472, 419, 436, 278, 496, 867, 210, 399, 680, 480, 51, 878, 465, 811,
            169, 869, 675, 611, 697, 867, 561, 862, 687, 507, 283, 482, 129,
            807, 591, 733, 623, 150, 238, 59, 379, 684, 877, 625, 169, 643, 105,
            170, 607, 520, 932, 727, 476, 693, 425, 174, 647, 73, 122, 335, 530,
            442, 853, 695, 249, 445, 515, 909, 545, 703, 919, 874, 474, 882,
            500, 594, 612, 641, 801, 220, 162, 819, 984, 589, 513, 495, 799,
            161, 604, 958, 533, 221, 400, 386, 867, 600, 782, 382, 596, 414,
            171, 516, 375, 682, 485, 911, 276, 98, 553, 163, 354, 666, 933, 424,
            341, 533, 870, 227, 730, 475, 186, 263, 647, 537, 686, 600, 224,
            469, 68, 770, 919, 190, 373, 294, 822, 808, 206, 184, 943, 795, 384,
            383, 461, 404, 758, 839, 887, 715, 67, 618, 276, 204, 918, 873, 777,
            604, 560, 951, 160, 578, 722, 79, 804, 96, 409, 713, 940, 652, 934,
            970, 447, 318, 353, 859, 672, 112, 785, 645, 863, 803, 350, 139, 93,
            354, 99, 820, 908, 609, 772, 154, 274, 580, 184, 79, 626, 630, 742,
            653, 282, 762, 623, 680, 81, 927, 626, 789, 125, 411, 521, 938, 300,
            821, 78, 343, 175, 128, 250, 170, 774, 972, 275, 999, 639, 495, 78,
            352, 126, 857, 956, 358, 619, 580, 124, 737, 594, 701, 612, 669,
            112, 134, 694, 363, 992, 809, 743, 168, 974, 944, 375, 748, 52, 600,
            747, 642, 182, 862, 81, 344, 805, 988, 739, 511, 655, 814, 334, 249,
            515, 897, 955, 664, 981, 649, 113, 974, 459, 893, 228, 433, 837,
            553, 268, 926, 240, 102, 654, 459, 51, 686, 754, 806, 760, 493, 403,
            415, 394, 687, 700, 946, 670, 656, 610, 738, 392, 760, 799, 887,
            653, 978, 321, 576, 617, 626, 502, 894, 679, 243, 440, 680, 879,
            194, 572, 640, 724, 926, 56, 204, 700, 707, 151, 457, 449, 797, 195,
            791, 558, 945, 679, 297, 59, 87, 824, 713, 663, 412, 693, 342, 606,
            134, 108, 571, 364, 631, 212, 174, 643, 304, 329, 343, 97, 430, 751,
            497, 314, 983, 374, 822, 928, 140, 206, 73, 263, 980, 736, 876, 478,
            430, 305, 170, 514, 364, 692, 829, 82, 855, 953, 676, 246, 369, 970,
            294, 750, 807, 827, 150, 790, 288, 923, 804, 378, 215, 828, 592,
            281, 565, 555, 710, 82, 896, 831, 547, 261, 524, 462, 293, 465, 502,
            56, 661, 821, 976, 991, 658, 869, 905, 758, 745, 193, 768, 550, 608,
            933, 378, 286, 215, 979, 792, 961, 61, 688, 793, 644, 986, 403, 106,
            366, 905, 644, 372, 567, 466, 434, 645, 210, 389, 550, 919, 135,
            780, 773, 635, 389, 707, 100, 626, 958, 165, 504, 920, 176, 193,
            713, 857, 265, 203, 50, 668, 108, 645, 990, 626, 197, 510, 357, 358,
            850, 858, 364, 936, 638 };

    /**
     * Return the random number at a specific index.
     *
     * @param i the index
     * @return the random number
     */
    static int rNums(int i)
    {
        return RNUMS[i];
    }

    private Bzip2Rand()
    {
    }
}
